This is a thing. It’s in BeyondETFs Pro. It shows how much more you’ve earned than if you had purchased shares of the Index (OEX = S&P 100 ETF).
At the moment of recorded purchase, an equivalent $ value of Index was also noted. Gap refers to the difference between what your actual proceeds are compared to what they might have been if you had purchased the Index. The Gap % is relative to the Index.
How big is your Gap?
Mine is 62.5% (it varies day by day). That means that my portfolio, using the Brockmann Method, is 62.5% HIGHER than if I had purchased the Index.